127 stalling
 

I have a Cub Cadet 127 that I have owned for a couple years. I bought it from a fellow that had no information about any service or repairs it has had.
I installed new genuine Kohler points and carburetor kit. Set the points and adjusted the valves and governor. The engine starts effortlessly within 1 or 2 seconds at any outdoor temperature. It idles great and will run all day at 1/4 throttle or less. But if I move the throttle past 1/4 position the engine speed will increase, run for 30 seconds or so and die. The more wide open I move the throttle the faster the engine stalls out. It refires and runs great the instant the throttle is lowered and I hit the key. I bushed the carb throttle shaft, rechecked the float and rechecked the intake and exhaust valve setting. I have not pulled the cylinder head so I don't know the condition of the valves etc. Any advice would be greatly appreciated.

Thanks DL127

sounds like a fuel problem , check the settlement bowl theres a screen in it . make sure it has good fuel flow out of the tank

Try enriching the main jet screw 1/2 turn and see how it acts after you check the fuel flow as suggested.
Also,
many times a piece of foreign material ( IE.fuel line hose) will become lodged in the fuel inlet fitting at the carb that leads to the needle valve.
Does pulling the choke help?
Another thing comes to mind:
A bad condenser can and will allow an engine to start normally and idle
at slow speed all day long,
but when the throttle is advanced, it will not rev up and will act like a fouled plug/missing/sputtering.:bigthink:

I agree with the others. There is some sort of Fuel Problem.

I replaced the condenser at the same time I replaced the points. I fabricated a stainless steel gas tank from 4" pipe, removed the settling bowl and installed new tubing, an inline fuel filter and petcock. I'm stumped. It has done this stall out thing since day one. When I rebuilt the carb I dismantled it and ran it through an ultrasonic bath cleaner and blew compressed air thru every port or hole I could see. I'm convinced it's fuel related as well but other than out right replacing the carb I don't know what to do. The only ignition part I haven't replaced is the coil. I haven't tried pulling the choke before it stalls. I will try opening the high speed screw 1/2 a turn.

Again, it is a FUEL issue.

Try running the tractor with the Gas Cap off. See if it is a "venting" issue.

The inline fuel filter could be a problem. See what kind of flow you get thru it.

Agree with R laruse
 

I would try a piece of hose straight through without the filter to eliminate this first. There is a difference filter to filter. if the filter has a check valve in it may require a fuel pump to flow, and gravity may not be enough to open it. Won't really cost you anything to try. if that's the problem investigate a free flowing ( gravity fed) filter
.

What RLause and budscub said. I had the same problem on my 129.

Installed a different carburetor. Engine still stalls out. What diameter fuel line should my 127 have?

Ya got a vented cap on that fancy shmancy new fuel tank??

Yes sir she's got a hole drilled in the cap, and I can see day light thru it. When I got the tractor it had a 1/4" od copper tubing fuel line with compression fittings. I replaced it with new 1/4" od copper tubing. The inside diameter is a bit over 1/8". I guess I'll replace the copper with larger id hose and maybe that will correct the issue.

1/4" OD Copper Line is just fine. Is there some sort of Fuel Filter (Gravity type) between the Tank outlet and Carb inlet..??

:bigthink:

How about a picture of your new tank setup?:WWP:

Regarding the copper fuel line.... Any kinks along the length will likely starve the fuel. Did you deburr or ream the ends of tube after you cut it to length? I prefer the rubber hose on my tractors.

I don't remember if I reamed the tubing after cutting. There is no filter only a fuel shutoff valve, tee, dirt leg and a drain valve. Like I said before this stall problem was present the day I bought it home. I'm going to increase the fuel line diameter.

Lets try something:
turn fuel off, then remove the fuel line @ the carb, and then turn the fuel on and see what the flow is, going into a catch can.

It looks like your plumbing is not getting you enough down hill flow, but pix's can give a false scene sometimes.
Also you could try removing the tank clamps and holding it up higher and starting the engine to see if it is still running out of fuel when you advance the throttle.

Oh, I like the tank you made,--- inventive BTDT :beerchug:

I agree with George.

I agree with the others here. It sounds like a fuel delivery issue. I'd do what George said in his last post. That fuel line looks plenty big enough.

I installed a new 5/16" id fuel hose. When its disconnected from the carburetor and fuel valve open fuel just pours out the hose. Also installed new coil, copper core spark plug lead, readjusted the valves, and timed/set the points with a timing light. The stalling problem is just as bad as before. I attached a separate 12 v battery to the + terminal on the coil after removing the existing coil power wire. Engine still did the same thing. Could the engine be so wore out that it just gives up after a minute or two?

Sounds like it's flooding itself.
Had a fellow in my shop w couple weeks ago w/a 1200
He had the carb so screwed up, main needle was 4-1/2 turns out for starters.
It was doing the same thing as yours.
Is it blowing fuel out of the carb?
Or blowing black smoke when this happens?

You make no mention of replacing the points to coil wire or spark plug, use a champion H10C or equivalent and gap to .025.

Remove the bowl nut, while holding the bowl on and see if you get a good flow out the hole.
The carb has a vent hole so fuel can flow in it you should check for blockage there.

I know the points have been replaced, did you clean the contacts?
Inspect them carefully and see if the plastic arm is broken, it happens.

I replaced the point wire 10 or 12 months ago. Points aren't dirty or broken. I just checked spark plug it is a Champion h10c. I gapped it today .025". Set the points with a timing light, S in the window of the blower housing. The carbs high jet screw 2 1/2 off the seat, low speed 1 3/4 off the seat. I have tried 1 1/4 off the seats but it runs worse and a shorter period of time.

Is your fuel tank vented? Remove the cap to see if that solves the problem. How quickly does it stall out? 15 seconds? 5 minutes?

Just to throw my 2 cents in I think ol George might have hit the nail on the head earlier when he mentioned the condenser a couple pages ago. It needs to be hooked up and the case of it grounded. Those cause goofy problems like you are talking about. If you have an extra one laying around it’s worth a try.

Try opening the main jet 3 turns off the seat and reported back to us.

Doesn't the manual call for 2 turns on the main and 2-1/2 turns open on the low speed jet? I've never had an engine fail/stall out at those settings, though proper operation always requires some tweaking from those settings.

And the condenser needs to be hooked up properly......between points and negative of coil.

A few posts back a fuel filter was mentioned. Is it a plastic with inline with paper inside? They do not flow well. Also. Have you set the float correctly? Good flow to carb is just half the battle. If the float is not set correctly good flow means nothing. It sounds like the problem is at the carb from what you have described. Starving for fuel.

In this pic, the hole at the bottom center of the carb inlet MUST be open to the fuel bowl area,,

https://sc02.alicdn.com/kf/HTB1KeJlf...x300.jpg_.webp

The choke plate has a cut out to clear that port.

I sent a carb to a "famous" rebuilder one time, and it came back with that port still blocked,,

Even he did not know that port was required to be open.

With that port blocked, the engine can not accelerate,,

I paid for a rebuild back then,, today, I would order a brand new carb from eBay for $12 delivered, and KNOW the carb is not the issue.

Also, I would get a new Kohler condenser,, because the issue is either the carb or the condenser,,, :bigthink:

I will solder a ground wire to the condenser strap and attach the other end to the - battery terminal. Condenser is a Kohler purchased 10 - 12 months ago. The point wire and condenser wire are attached to the - side of the coil. This problem has been present since day 1. I have only owned the tractor 2 years. I took a video of the carb venturi with the engine running/stalling out but I can't figure out how to post it. There appears to be plenty of fuel but that's my opinion. I captured a screen shot of the butterfly, fuel appears blurry in front of the butterfy. Carb is a brand new Chinese one. It stalls out just as good as the original.

DL you mentioned in post #5 that you hadn’t tried pulling the choke yet to see if symptom improves. Have you done that and if so what are the results?

That's a good question..... The answer to this would be quite significant and helpful!

I tried adjusting the choke to correct the stalling condition. It was no help whatsoever. I checked the float height on my new carburetor its 11/64". Tried adjusting high speed jet 3 turns off the seat. No help whatsoever. I ran a ground wire from the condenser strap to the - battery terminal. No difference. I checked the running at idle voltage at the terminal on the points its varies between 6 -7.5 volts. Also - terminal on the coil same 6 - 7.5 volts. I hooked a jumper wire from the + terminal of the battery to the + terminal of the coil. I still get 6 -7.5 volts between the points and - battery terminal. When the key switch is off I have 13+ volts across the battery. When the engine is running at idle the voltage is all over the place across the battery terminals or at the starter generator it varies between 6 - 12 volts. Could the erratic voltage contribute to the stalling issue?

I'm trying to understand this....Are you saying that when the engine is running, that you DO NOT have a steady 12 to 14 volts across the battery terminals and you DO have steady 12-13 volts across across the battery terminals when the engine and key are off. Is that what you are saying?

Also someone asked how long it runs before it dies, you never indicated that.

Yes I thought my digital volt ohm meter was bad. Tried a different one same erratic voltage.

It will idle all day long. Advance the throttle a bit the engine does within 20-30 seconds. Pull the throttle back it fires instantly and will run until it empties the tank.

I'd look around and make sure all the wiring connections are clean and tight. It might be possible the electrical could be shorting, especially when running and under vibration.

The voltage across the battery should not be eratic, especially at idle.
Not doubting you, but are you sure the meter is set to measure dc volts?
Also, just to double check, do you:
A. Have the wire from the points attached to the Negative (-) post on the coil?
B. Have the pigtail lead of the condenser attached to the same post on the coil as the points wire, i.e the negative (-) post?
C. Have the wire from the ignition switch via the wire harness attached to the positive (+) post on the coil?

With the key off, engine not running, measuring at the positive coil post to ground you should see no voltage.

With the key on, engine not running, measuring at the positive coil post to ground you should see the same voltage as you see at the battery's positive post.

With the key on, engine not running, measure the coil negative post to ground. You should see either the same voltage as the positive post if the points are open, or no voltage if they are closed. Rotate the engine by hand to open and close the points to verify your reading.

Report back what you find.

Battery voltage across the posts is 12.58 volts. The wire to the points is landed on the - terminal on the coil as is the condenser wire. The + side of the coil has a black wire on it that disappears into the harness behind the starter generator. When the key switch is off I have .000 volts at the + coil terminal. With the key on engine not running I have 12.55 volts at the + coil terminal. Key on points open = 12.43 volts at - coil terminal. Key on points closed = .16 volts at - could terminal. I did 2 compression checks per the service manual. The 1st one electrically with the starter turning the engine over, with the compression release probably releasing I got 40 psi. The 2nd check I removed the pto guard and wrapped a cord around the pulley rotating the engine backwards like the service manual states. I got 90 psi. It was a difficult pull because of the small diameter of the pulley. The manual states 100 psi is the lowest acceptable reading. Maybe I need to pull the head and check for bad valves or worn rings/bore.

Also the spark plug is very black and sooty. It's only had 3/4 of a gallon of fuel through it since I last had the plug out and cleaned it.